Reportable Segments - Reconciliation of Total Reportable Segments' Revenues and EBITDA to Consolidated Revenues and Consolidated Income Before Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment revenues	$ 463,526	$ 500,140
Amortization of Intangible Assets	(16,185)	(18,164)
Depreciation expense	(10,300)	(10,100)
Severance, restructuring, and acquisition integration costs	3,619
Operating income	29,708	47,490
Interest expense, net	(13,324)	(13,988)
Total non-operating pension benefit	699	603
Consolidated income from continuing operations before taxes	17,083	34,105
Reportable Segment
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment revenues	463,526	500,140
Total Segment EBITDA	60,239	76,299
Amortization of Intangible Assets	(16,185)	(18,164)
Depreciation expense	(10,282)	(10,103)
Severance, restructuring, and acquisition integration costs	3,619	0
Amortization of software development intangible assets	(330)	(59)
Purchase accounting effects related to acquisitions	20	0
Intersegment Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Segment Elimination	$ (95)	$ (483)